The present invention relates to transmission arrangements for amphibious vehicles, and in particular to control aspects thereof.
It is known for amphibious vehicles to have road wheels which can be retracted above the water line for use of the vehicle on water. This has the advantage of reducing hydrodynamic drag; particularly where the vehicle is designed to plane over the surface of the water, as such vehicles travel faster than displacement vehicles.
Where such wheel retraction systems are fitted, and the road drive and marine drive are driven in parallel, for example as disclosed in the applicant's co-pending application published as WO 02/07999, it is preferable to disconnect road drive on water. An example of road drive disconnection is disclosed in WO 02/14092, also of the present applicant. In this disclosure, a decoupler is provided in each wheel driveshaft. Such decouplers have many virtues, but light weight and simplicity are not among them.